what flipped her from Derek's power back to Adrian's
Presumably, she identified something about Adrian, both in #71 and #73, as well as in #19-22, that enabled her to recognize Adrian as her master over Derek. My take: in #19, Derek 'activates' Dani, at which point she remembers the watch and everything else, and for some reason - whether that's Adrian's winning over Derek, or Dani's recognizing that there's no way a loser like Derek could be her true master, or some other reason - Dani recognizes Adrian as her master. She even talks to Jacqui later about how she had been negligent in her duties.
Then, Adrian tells her to wake up. She forgets all about the watch, about the incident with Derek, about seducing Adrian, about enslaving all her roommates and Marliese, and is given the update while she was 'out'. She agrees, reluctantly, to go to Derek's place to be 'reactivated', and the plan is to take her away from Derek quickly, so that she can then return and use the watch to free the others and, in Jacqui's case, to allow her to wear clothes again. Things do not go quite according to plan, but ultimately they succeed, with all four of the rescued women now identifying Adrian as their master.
why does Marliese keep getting credit for finishing Jacqui's programming
Issue #72. Marliese picks up the watch and activates it, somehow. Then Mallory and Erin complete Jacqui's slavery.